A wide variety of biological and biochemical analyses employ fluorescence detection techniques to measure biological interactions. In particular, reactants in a given biochemical reaction may be provided with or may inherently possess fluorescent or fluorogenic groups that, upon illumination with light of an appropriate excitation wavelength, will emit a characteristic fluorescent signal. Depending upon the nature of the analysis, the changed property of the fluorescent group before, during and/or after a given reaction may provide an indication of the progress of the reaction, providing a readily monitorable signal associated with that progress. For example, the localization of a fluorescently labeled probe on a position of a solid support bound compound provides an indication of the affinity of the compound for the probe, e.g., as in the case of oligonucleotide arrays. Alternatively, shifts in the electrokinetic mobility of the fluorescent species may provide an indication of a change in the charge of the fluorescent group, e.g., arising from phosphorylation, cleavage, association with oilier charged species, or the like. In still other systems, immobilization of fluorescent monomers by support bound synthesis complexes may provide an indication of the incorporation of such monomers into polymeric species, by the complexes, e.g., polymerase/template/primer complexes.
With increasingly complex and demanding analytical processes comes a need for sensitive and flexible detection systems. The present invention provides such systems, their constituent components and methods for using them.